Castleton-on-Hudson, New York has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.4 °C (low) to 15.3 °C (high). Annual precipitation averages 1048.3 Millimeters. Castleton-on-Hudson is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.5 °C | 0.7 °C | 67.56 mm |
| February | -7.8 °C | 2.3 °C | 55.63 mm |
| March | -3.2 °C | 7.4 °C | 74.17 mm |
| April | 3.1 °C | 15.1 °C | 80.77 mm |
| May | 9.1 °C | 21.7 °C | 86.36 mm |
| June | 14.3 °C | 26.2 °C | 112.78 mm |
| July | 16.9 °C | 28.6 °C | 111 mm |
| August | 16.1 °C | 27.6 °C | 103.38 mm |
| September | 11.7 °C | 23.7 °C | 99.82 mm |
| October | 5.6 °C | 16.7 °C | 102.36 mm |
| November | 0.3 °C | 9.7 °C | 72.9 mm |
| December | -4.6 °C | 3.6 °C | 81.53 mm |
| Annual | 4.4 °C | 15.3 °C | 1048.26 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |